First, let me say that the following is 100% my opinion. I don't have 200 pages of documentation to back up anything I say below. I am just giving my perceptions, observations, and conclusions as I see them in response to the question asked.
I have both and like both. They will both do a good job for you, and I wouldn't neccessarily call either of them "low end". The BK7 is less expensive than the RAT-7, has better fit and finish out of the factory than the Rat-7, and it is a little pointier. The handles on the BK7 are very large, and, though I like them, are sometimes not well tolerated. Contrast that with the Rat-7 micarta which has a much wider range of comfort (especially if you take a little sandpaper and round off the edges). The Rat-7 comes in a better sheath than the BK7. The Bk7 doesn't have a finger choil and the Rat-7 does.
ergonomics- Rat-7 (the finger choil does it for me)
toughness- dead heat
fit and finish- BK7 wins hands down
price- BK7
sheath- Rat-7
support after the sale- Rat-7 (Jeff Randall and Mike Perrin take care of anything that might happen to you, I don't know how their service was before, but I would think that with Camillus going under, that your chances of a replacement due to failure would be slim if they aren't being produced any more, though, I am sure that if Ethan Becker has anything to say about it, you would be well taken care of)
Perception by public- Rat-7 the BK7 just looks more menacing (asked wife, and four people over for a bbq, the opinions were unanimous)
After all that, if I could only have one of them for woods use, I would have to give the edge to the Rat-7...The finger choil makes a world of difference in the precision and comfort aspects when doing fine work with a large knife.
I hope this helps you out.